Medical Comorbidity and Male Sex Are Associated With Higher In-hospital Mortality for 90-Day Readmissions and Higher Readmission Rates After Nonelective Primary Total Hip Arthroplasty for Hip Fracture.

Abstract

Purpose: To assess whether sex and comorbidity are associated with the risk of 90-day readmission and associated mortality after nonelective primary total hip arthroplasty (THA) for hip fracture in the United States.

Methods: We used the 2016-2019 US Nationwide Readmissions Database, a nationally representative dataset of readmissions, to examine 90-day readmission outcomes after primary nonelective THA with a primary diagnosis of hip fracture. Sex and medical comorbidity (Deyo-Charlson Comorbidity Index) were variables of interest. We adjusted for demographics (age), social determinants of health (income, region, insurance payer), and hospital characteristics (control, location/teaching status, bed size). We calculated adjusted odds ratio (aOR) and 95% confidence intervals (CIs) in multivariable-adjusted logistic regression analyses.

Results: Of the 346,030 nonelective primary THAs for hip fracture performed in the United States, 61,443 (17.8%) had a 90-day readmission. For readmitted patients, the mean age was 80.2 years (SD, 9.6), 62.0% were women, and 90.6% had Medicare payer. In multivariable-adjusted analysis, compared with men, women had a lower aOR of 0.75 (95% CI, 0.73-0.77; p < 0.001) for 90-day readmission and lower aOR of 0.76 (95% CI, 0.69-0.84; p < 0.001) of in-hospital mortality during readmission, after nonelective primary THA for hip fracture. Deyo-Charlson index scores of 1 and ≥2 were associated with higher aOR of 90-day readmission at 1.53 (95% CI, 1.47-1.59; p < 0.001) and 2.20 (95% CI, 2.13-2.28; p < 0.001) and higher in-hospital mortality during readmission, 1.20 (95% CI, 1.01-1.42; p = 0.04) and 1.69 (95% CI, 1.40-1.97; p < 0.001), respectively.

Conclusion: In contemporary U.S. national data from 2016 to 2019, medical comorbidity and male sex were each associated with a higher risk of 90-day readmission and in-hospital mortality following primary nonelective THA for hip fracture. Further investigation into mechanisms and pathways of increased risk in men and those with higher medical comorbidity undergoing primary THA for hip fracture is needed, which can lead to the development of pathways for risk reduction and improved outcomes.